In recent years, image capturing devices, such as digital cameras, have rapidly become widely used, with the high functions as well as the shift to low prices. Further, a large number of these image capturing devices have been incorporated in portable information terminal devices, which are always been able to capture images very simply, and are highly valued and widely used. Along with the popularization of digital image data, the digital image data has been accepted for ID photograph or evidential photograph to be filed, and which have been used as a photograph with certification.
It is easily to make interpolations of the captured digital image data, due to its inherent characteristics. Further, it is also possible to change the digital image data, leaving almost no trace of working, comparing to a silver halide photograph. Accordingly, if the digital image data is wrongly interpolated and filed as an ID photograph or an evidential photograph, it is very difficult to judge whether it is the original image, which can result in much damage. Therefore, interpolation-proof technologies of the image data have been proposed using digital watermarking or PKI (public key infrastructure) (see Patent Documents 1 and 2). Further, services are available to verify the authenticity of digital data (being untampered state of digital data) using evidence issued by a third organization, such as Certificate Authority.
Further, the above image capturing devices can be broadly classified into a camera module to capture the image and output its image data, and an image capturing device main body (hereinafter referred to as a main unit) to record and display the outputted image data. By this classified structure, the camera module can be treated as a single module, and can generally be used independently from the other features of the connected main unit, which improves convenience in the manufacture of the image capturing devices.    [Patent Document 1] Unexamined Japanese Patent Application Publication No. 11-308,564    [Patent Document 2] Unexamined Japanese Patent Application Publication No. 2001-78,014